Studied by 50 people
Commonalities of All Living Organisms
Evolution, order/organization, reproduction, growth and development, energy processing, internal regulation, response to the environment
Levels of Life
Biosphere, Ecosystems, Communities, Populations, Organisms, Organ Systems, Organs, Tissues, Cells, Organelles, Molecules, Atoms
Taxa of Life
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Central Theory of Biology
Evolution by means of natural selection
Scientific Method
Observation, Hypothesis, Experiment, Data collection, and Conclusions
Matter
A substance that takes up space, has mass, is comprised of elements, and can exist as a solid, liquid, gas or plasma.
Important Elements for Life
Oxygen, Carbon, Hydrogen, and Nitrogen
Atomic Number
Number of protons in an element
Atomic Mass
Number of protons and neutrons in an element
Subatomic Particles
Proton, Neutron, Electron
Isotope
Same element, but a different number of neutrons and a different mass
Covalent Bonds
form when atoms share electrons to achieve stability.
Polar Covalent Bonds
occur when two atoms share electrons unequally due to a difference in electronegativity.
Ionic Bonds
form between atoms with different electronegativities.
Hydrogen Bonds
occur when atoms share electrons unevenly due to a difference in electronegativity, creating a dipole moment.
Van der Waals Interactions
weak attractive forces between molecules or atoms. They occur because of temporary fluctuations in electron distribution, creating temporary dipoles.
Dynamic Equilibrium
a state in which the forward and reverse processes occur at equal rates, resulting in a constant concentration of reactants and products.
Properties of Water that Contribute to Earth’s Suitability for Life
Ice floats, surface tension, specific heat, solvent.
High pH
Basic, OH-
Low pH
Acid, H+
Buffer
Minimizes changes in pH, weakly ionizing
Mechanism
Living chemistry is complex, but reproducible. Molecules from living organisms can be reproduces from non-living sources.
Vitalism
Living molecules only come from living sources. There is a “living force” found only within organisms that are alive, which is surrendered at death.
Structural Isomers
Different covalent arrangements of their atoms
Cis-trans Isomers
Same covalent bonds but differ in spatial arrangements
Enantiomers
Isomers that are mirror images of each other
Functional Groups
The components of organic molecules that are most commonly involved in chemical reactions
OH
Hydroxyl
COOH
Carboxyl
C=O
Carbonyl
-SH
Sulfhydryl
-NH2
Amino
-PO42-
Phosphate
CH3
Methyl
Macromolecules
Polymers built from monomers; formed by dehydration synthesis, broken down by hydrolysis
Carbohydrates
Sugars and polymers of sugars
Monomers
Single parts of repeating units that serve as building blocks
Polysaccharides
Polymers of sugars with storage and structural roles
Lipids
Not true polymers; hydrophobic; fats, phospholipids, steroids
Fat
Glycerol (3 carbon alcohol with hydroxyl group) and fatty acid (carboxyl group with carbon skeleton)
Steriods
Lipids characterized by a carbon skeleton consisting of four fused rings.
Proteins
More than 50% of the dry mass of most cells; functions include structural support, storage, transport, cellular communications, movement, and defense against foreign substances.
Amino Acid Structure
Amino group + alpha-carbon + carboxyl + R-group
Primary structure
Unique sequence of amino acids
Secondary Structure
Coils and folds in the polypeptide chain
Tertiary structure
Interactions among various side chains (R-group)
Quaternary structure
Consists of multiple polypeptide chains
Nucleic Acids
Store, transmit, and express hereditary information
Types of Nucleic Acids
RNA and DNA
Nucleotides
nitrogenous base + pentose sugar + phosphate group
Purines
A + G
Pyrimidines
C + T + U
Compound Light Microscope
Visible light is passed through a specimen and then through glass lenses
Transmission-Electron Microscope
Focuses a beam of electrons through a specimen
Scanning Electron Microscope
Focuses a beam of electrons onto the surface of a specimen, providing an image that looks 3D
Cell Fractionation
Takes cells apart and separates the major organelles from one another.
Prokaryotic Cells
Bacteria and Archaea; No nucleus, no membrane-bound organelles
Eukaryotic Cells
Fungi, Animals, Plants, and Protists; Cytoskeleton, Membrane-bound organelles, DNA in a nucleus.
Nuclear Envelope
A double membrane that encloses the nucleus, separating from the cytoplasm.
Ribosomes
Particles made of ribosomal RNA and protein. Carry out protein synthesis.
Rough ER
Surface studded with ribosomes; distributes transport vesicles, is a membrane factory for the cell.
Smooth ER
Synthesizes lipids, metabolizes carbohydrates, detoxifies drugs and poisons, and stores calcium ions.
Golgi Apparatus
Modifies products of the ER, manufactures certain macromolecules, sorts and packages materials into transport vesicles.
Transport Vesicles
Proteins surrounded by membranes
Lysosome
A membranous sac of hydrolytic enzymes that can digest macromolecules.
Vacuoles
Food vacuoles, Contractile vacuoles, and Central vacuoles.
Endosymbiont Theory
An early ancestor of eukaryotic cells engulfed a non-photosynthetic prokaryotic cell, which formed an endosymbiont relationship with its host.
Mitochondria
Cristae, matrix, inner-membrane space; home of Krebs cycle and oxidative phosphorylation.
Chloroplasts
Contain the green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis.
Granum
Stacks of thylakoids in the chloroplast
Structural Members of Cytoskeleton
Microtubules, Microfilaments, Intermediate filaments
Microtubules
Thickest of the three components; Cell motility, chromosome movements, organelle movements.
Microfilaments
Actin filaments, thinnest components; Cell motility, cell shape, cell division.
Intermediate filaments
Middle range components; Anchorage of nucleus, formation of nuclear lamina.
Intercellular Junctions
Desmosomes, tight junctions, gap junctions, plasmodesmata.
Desmosomes / Anchoring Junctions
Fasten cells together into strong sheets
Tight Junctions
Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid.
Gap Junctions / Communicating Junctions
Provide cytoplasmic channels between adjacent cells.
Plasmodesmata
Channels that perforate plant cell walls.
Extra Cellular Matrix
ECM proteins bind to receptor proteins in the plasma membrane called integrins
Fluid Mosaic Model
A membrane is a fluid structure with a “mosaic” of various proteins embedded in it.
Selective permeability
Small, non-polar molecules can pass through phospholipid bilayer
Tonicity
The ability of a surrounding solution to cause a cell to gain or lose water.
Isotonic Solution
No net water movement across the plasma membrane
Hypertonic Solution
Cell loses water
Hypotonic Solution
Cell gains water
Passive transport
Diffusion of a substance across a membrane with no energy investment
Active transport
Uses energy to move solutes against their gradients.
Bulk transport
Large molecules cross the membrane via vesicles
Exocytosis
Transport vesicles migrate to the membrane, fuse with it, and release their contents
Types of Endocytosis
Phagocytosis, pinocytosis, receptor-mediated endocytosis
Phagocytosis
Cellular eating
Pinocytosis
Cellular drinking
Receptor-mediated endocytosis
Ligand joins a receptor to signal coat proteins to start endocytosis.
1st Law of Thermodynamics
Energy can be transferred and transformed, but it cannot be created or destroyed.
2nd Law of Thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
Metabolism
The totality of an organism’s chemical reactions
Anabolism
Consume energy to build complex molecules from simpler ones.
Catabolism
Release energy by breaking down complex molecules into simpler compounds.
Gibbs free energy
Energy that can do work when temperature and pressure are uniform, as in a living cell.
